Removal efficiency for micro-polystyrene in water by the oil-based ferrofluid employ response surface methodology

This research article presents a study on the potential use of oil-based ferrofluid for the efficient removal of microplastics from water. The targeted analyte, micro-polystyrene (micro-PS), was chosen along with palm oil as the carrier liquid. Fourier Transform Infrared (FTIR) analysis was conducted to identify the main peaks in the ferrofluid, including carboxyl group (1542 cm-1), C-H bonding (1022 cm-1), CH2 bonding (2941 cm-1), CH3 bonding (3461 cm-1), C=C bonding (1255 cm-1), and Fe-O (597.34 cm-1). A comprehensive investigation of the synergistic effect of six variables was performed: volume of oil (4-15 mL), weight of magnetite nanoparticles (0.1-0.2 g), stirring rate (132-468 rpm), contact time (3-12 min), pH value of water samples (pH 6-8), and effect on ionic strength (0-16 g/L). Response surface methodology, including 26 -Plackett-Burman and 24 -central composite design, were employed to establish the relationship between the variables. The optimum operational settings proposed by the model were as follows: volume of oil (14.6 mL), weight of magnetite nanoparticles (0.1 g), stirring rate (216 rpm), contact time (3.29 min), pH value of water samples (pH 6-6.5), and effect on ionic strength (16 g/L), resulting in a remarkable removal efficiency of 91.09 ± 0.99%. The method exhibited desirable figures of merit, including a low bias (%RSD) of below 5% and the ability to reuse the ferrofluids for up to five cycles. Additionally, an analytical greenness metric was employed to assess the environmental impact of the sample preparation process, with a green score of 0.69/1.0 (indicating a light green colour). Future work in this field could focus on the scalability of the developed method and its applicability to real-wastewater treatment

Detection of microplastics in human colectomy specimens

Abstract Background and Aim While dietary exposure to microplastics is increasingly recognized, it is unknown if ingested plastics remain within the digestive tract. We aimed to examine human colectomy specimens for microplastics and to report the characteristics as well as polymer composition of the particles. Methods Colectomy samples were obtained from 11 adults (mean age 45.7, six males) who were residents of Northeastern Peninsular Malaysia. Microplastics were identified following chemical digestion of specimens and subsequent filtration. The samples were then examined for characteristics (abundance, length, shape, and color) and composition of three common polymer types using stereo‐ and Fourier Transform InfraRed (FTIR) microscopes. Results Microplastics were detected in all 11 specimens with an average of 331 particles/individual specimen or 28.1 ± 15.4 particles/g tissue. Filaments or fibers accounted for 96.1% of particles, and 73.1% of all filaments were transparent. Out of 40 random filaments from 10 specimens (one had indeterminate spectra patterns), 90% were polycarbonate, 50% were polyamide, and 40% were polypropylene. Conclusion Our study suggests that microplastics are ubiquitously present in the human colon